Amphotericin b, its production, and its salts



Oct. 13,1959 J. D. DUTCHER ET AL 2,903,611

AMPHOTERICIN B, ITS PRODUCTION, AND ITS SALTS Filed Dec. 28, 1954 2 Sheets-Sheet 1 FIGURE 1 I INFRARED ABSORPTION SPECTRUM OF ANPHOTERICIN A WAVELENGTH (mcnons) JOHN VANDEPUTTE B WwKr/L'W Oct. 13, 1959 J. D. DUTCHER ETAL 2,998,611

AMPHOTERICIN B, ITS PRODUCTION. AND ITS SALTS Filed Dec. 28, 1954 2 Sheets-Sheet 2 i O O (ALISNJG 1V3l1d0) zouveuossv 3mm IANE5 D. BUTCHER WILLIAM GOLD JOSEPH F. PAGANO TOHN VANDEPUTTE United States Patent AMPHOTERICIN B, ITS PRODUCTION, AND

. ITS SALTS Application December 28, 1954, Serial No. 478,014 7 Claims. (Cl. 167-65) This invention relates to new and useful antibiotics, and to methods for their production. More particularly, it relates to new antibiotics in various forms, and to processes for producing them by fermentation, as well as concentrating, purifying and isolating them, and producing their salts. In its free from; one of the two new antibiotics that have been isolated is called amphotericin A; and the other new antibiotic is called amphotericin B; and the unmodified term amphotericin is employed herein to generically designate these two antibiotics and their admixture.

The antibiotics of this invention are formed by the cultivation, under controlled conditions, of a hitherto undiscovered species of Streptomyces.

THE MICROORGANISM The microorganism useful for the preparation of amphotericin is a newly discovered species of Streptomyces isolated from a sample obtained at Tembladora on the Orinoco River in South America. A culture of the living organism has been deposited, and made a part of the stock culture collection of, the Rutgers Institute of Microbiology (New Brunswick, New Jersey), from whence it is available; and it has been assigned the number 3694 in the Waksman collection, and is hereinafter designated as Streptomyces nodosus.

It is to be understood that the invention is not limited to the use of the particular organism described herein, but includes, inter alia, mutants produced from the described organism by mutating agents, such as X-rays, ultraviolet radiation and nitrogen mustards.

For isolating and characterizing the microorganism, a

portion of the soil sample is shaken in sterile distilled water and plated on Henrici agar medium. This medium contains:

The medium is adjusted to pH 7.0, and sterilized in an autoclave at 121 C. for 20 minutes. After 7 to 10 days incubation at 25 C., colonies of Streptomyces nodosus are isolated from the plated soil. These isolated colonies are then grownon an agar medium which contains:

Gm. Bacto tryptone 5 Malt extract a 3 Glucose 10 Yeast extract 3 Distilled water to 1 liter.

The agar is autoclaved at 121 C. for fifteen minutes.

2,908,61 l Patented Oct. 13, 1959 The microorganism, when tested by the streak plate procedure on yeast beef agar for antibiotic activity against both bacteria and fungi, does not inhibit any of the test bacteria, but does inhibit the test fungi Saccharomyces cerevisiae, Rhodotorula glutinis, Candida albicans, and Aspergillus niger.

The following is a description of colonies of the microorganism incubated for various times and on various media:

Potato plug-After 15 days, growth is spreading, very heavy, moist, tough, about the same color as the potato, white spores covering part of the growth on the slant portion.

Litmus milk.-In 7 days, the ring of growth at the surface is colorless. The milk turns blue-purple, clearing gradually from the top toward the bottom, indicating proteolysis without coagulation.

Czapek-Dox agar.NaNO KCl, 0.5 gm.; MgSO .7H O, 0.5 gm.; FeSO .7H O, 0.01 gm.; glucose, 40 gm.; agar, 15 gm.; distilled water to 1,000 ml.

No growth in 15 days, in spite of two inoculations.

Glucose-natrient-brom cresol purple agar slant-Beef extract, 3 gm.; proteose peptone, 10 gm.; glucose, 10 gm.; NaCl, 5 gm.; agar, 20 gm.; brom cresol purple, 0.15 gm.; distilled water to 1,000 ml. pH 7.0.

Moderately heavy growth in 51 days, wrinkled, shiny, asporogenous. The wrinkling on all agars is very characteristic. The wrinkles are parallel, straight-line indentations in the culture at right angles to one another, giving a stone wall appearance with rectangles of various sizes.

Sabouraud agar slant.-Glucose, 40 gm.; neopeptone, 10 gm.; agar, 15 gm.; distilled water, 1,000 ml.

At four days, the culture is yellow, turning brownish at seven days, all brown at fifteen days. Growth is heavy, first shiny, then turning dull, wrinkled with a brown diffusible pigment visible by three to four days.

Glucose-asparagine agar slant.Glucose, 10 gm.; K HPO 0.5 gm.; asparagine, 0.5 gm.; agar, 15 gm.; distilled water, 1,000 ml.

At seven and fifteen days, growth is moderately heavy, unwrinkled, colorless, with white spores turning gray, and a yellow difiusible pigment turning brownish. In addition, a water-insoluble, deep yellow material is de posited in the edges of the agar slant at the base of the slant. This material is soluble in methanol, propanol, and dimethyl formamide.

The microorganism is further characterized by the fact that hydrogen sulfide is not produced as evidenced by the lead acetate paper test in a medium containing: Proteose peptone, 20 gm.; glucose, 1 gm.; Na HPO 2 gm.; agar, 2 gm.; and distilled water to 1 liter. The culture grows as a white, asporogenous pellicle. Furthermore, Difco gelatin is liquified. The culture grows as a light brown, asporogenous ring at the surface. Still further, in Difco nitrate broth, the culture grows as a light brown asporogenous pellicle. The broth darkens with a diffusing brown pigment. Nitrate is strongly reduced to nitrite. Additionally, starch is hydrolyzed by the culture when grown in a medium containing starch.

To determine the carbon and nitrogen nutrition of Streptomyces nodosas, tests were made as follows: Four series of tubes of mineral salts agar are prepared with '1 mg. per ml. of these four nitrogen sources respectively: (NH SO NaNO asparagine, and casein hydrolysat'e. In each series, each tube is fortified with 10 mg. per ml. of one of sixteen possible carbon and energy sources. These are starch, inulin, dextn'n, raffinose, maltose, lactose, sucrose, sorbose, glucose, dulcitol, inositol, sorbitol, mannitol, xylose, arabinose, and glycerol.

The agar in the tubes (10 ml.) is slanted, and the slants are streaked with a suspension of Streptomyces nodosus spores in distilled water. After 9 days incubation, the growth was examinedv and is described in Table I followas a mineral acid (e.g. hydrochloric acid, sulfuric acid or phosphoric acid) to precipitate the crude amphotericin. (3) The pH of the Whole broth is adjusted either to a such as sodium hydroxide or potassium hydroxide. The

ing.

5 value of about 2 to 3 (by treatment with an acid) or a [Nitrogen source, 1 mg./ml.]

TABLE I.GROWTH OF STREPTOMYCES NODOSUS FOR NINE DAYS ON VARIOUS CARBON AND NITROGEN SOURCES Carbon and Energy (N H9 80, N aNO Asparaglne Casein Hydrolysate Source, 10 mg./ml.

none 0 0 sparse, white spores sparse, gray spores.

starch scanty, asporogenous 0 heavy, brown mycelium, brown diffusible heavy, brown mycelium, brown dlfruslble pigment, asporogenous. pigment, asporogenous.

irmlin 0 0 sparse, white spores sparse, white spores.

dextrin scanty, asporogenous 0 heavy, brown mycelium, brown dlfiusible heavy, brown mycelium, brown difiusiblo pigment, asporogenous, yellow deposit pigment, asporogenous yellow deposit 1J1 agar. m agar.

rafii'nnse 0. 0 sparse, white spores sparse gray spores.

maltose scanty, asporogenous. 0 heavy, brown mycelium, some white spores, heavy, brow-n growth, asporogenous, brown brown diifusible pigment, yellow deposit dlffuslble pigment, yellow deposit. 1 agar.

lactose do 0 heavy, brown mycelium; asporogenous moderate, black mycelium, gray spores brown difiusible pigment. near butt.

sucrose barely germinated 0 moderate, White spores moderate, gray spores.

sorbo n 0 scanty, asporogencus scanty, gray spores.

glucose scanty, asporogenous 0 heavy, brown mycelium, some white heavy, brown mycelium, asporogeuous,

brown diiIusible pigment yellow deposit. brown difiusible pigment, yellow deposit.

dulcitol barely germinated 0 scanty, whitespores scanty, gray spores.

inosit0l. scanty, asporogenous 0 moderate, white spo moderate, spores gray, sporulation heavy.

sorbitol. barely germinated 0 0 scanty, inhibited.

mannit moderate asporogenous 0 heavy, brown mycelium, some white spores, heavy, brown mycelium, asporogenous,

brown difiusible pigment. brown difiusible pigment.

xylnse barely erminated 0 moderate, white spores scanty, inhibited.

arnhinnse (in 0 0 0.

glycerol do 0 moderate brown mycelium, some white heavy, brow-n mycelium, asporogenous brown spores, brown dlfiuslble pigment. difiusible pigment.

Nora-0 indicates no growth.

THE ANTIBIOTICS Streptomyces nodosus produces a mixture of antibiotics. The mixture itself, as well as the specific antibiotics isolated from said mixture, possesses a wide antifungal spectrum, but no significant antibacterial properties.

In order to form amphotericin, Streptomcyes nodosus is grown at a suitable temperature of from 23 C. to C., preferably about 25 C., under submerged aerobic conditions in an aqueous nutrient medium containing an assimilable, fermentable carbohydrate source and an assimilable nitrogen source. Suitable carbohydrate sources, as indicated above, include: starch; dextrin; sugars, such as maltose, lactose, and glucose; glycerol; etc. Suitable nitrogen sources include asparagine, casein hydrolysate, soybean meal, beef extract, yeast extract, etc. The fermentation is carried out for about 24 to 150 hours. At the end of this period of time, a substantial amount of amphotericin has been formed (as shown by bioassays), as more fully disclosed in the examples.

After growth has been completed, amphotericin is separated from the culture by any one of the three following alternative methods: (1) The mycelium is separated from the whole broth by filtration or centrifugation,

and amphotericin is extracted from the mycelium, after lowering the pH of the mycelium to about 2 to 3 by treatment with an acid. The extraction is done with a suitable solvent such as a lower alkanol (e.g. isopropanol, n-propanol or n-butanol). Evaporation of the alkanol causes precipitation of the crude amphotericin. (2) The whole broth is alkalinized to a pH about 11, and preferably to a pH of about 12, by means of a base broth isv then agitated and filtered, and the filtrate is neutralized to a pH of about 7 by means of an ac S SA value of 10 to 11 (by treatment with a base), since amphotericin is more soluble at these pH ranges. The broth is then extracted with a suitable extracting agent, such as the alkanols previously listed; filtered; and the phases are separated (if n-butanol is used). The crude amphotericin is then directly precipitated from the filtrate by neutralizing to a pH of about 7 and removing a portion of the extracting agent by vacuum distillation.

Further purification of the crude amphotericin isolated by any one of these processes results in fractionation into its two components, amphotericin A and amphotericin B. This fiactionation is carried out by either one of the following processes:

(1) The precipitate of crude amphotericin is slurried in an alcohol, such as a lower alkanol (e.g. methanol, n-propanol, isopropanol, and butanol) at a low pH (obtained by treating the slurry with an acid such as a mineral acid) and filtered. The insoluble material consists mainly of crude amphotericin B. The filtrate is neutralized with a base, such as sodium hydroxide, to cause formation of a precipitate of purified crystalline material, representing primarily amphotericin A.

(2) The precipitate of crude amphotericin is slurried in a solvent, such as a di(lower alkyl) lower alkanoic acid amide (e.g. dimethyl formamide, dimethyl acetamide or diethyl formamide) and filtered. The insoluble material consists mainly of crude amphotericin B. By treating the amide solution with a mixture of water and an organic polar solvent, such as aqueous alcohol (e.g. a methanol-water solution) or an aqueous ketone (e.g. an acetone-water solution), a crystalline precipitate comprising mainly amphotericin A is obtained.

Amphotericins A and B are amphoteric substances which easily form salts with both bases and acids. Thus by treating amphotericin with an inorganic base, such as an alkali metal base (e.g. sodium hydroxide or potassium hydroxide) or an alkaline earth metal base, the corresponding metal salt is formed. By treating amphotericin Example 1.--Tank fermentation of Streptomyces nodosus An 800-gallon batch of Streptomyces nodosuls' is fermented with the inoculum medium, time, and conditions tabulated below.

Inoculum preparation:

A. First stage Inoculum source: culture Streptomyces nodosus,

grown on Gould agar slants. Medium:

3% Staleys Nutrient 4S 2% glucose .0005 CoCl .'6H O -1% CaCO pH adjusted to 7.0-7.2 I Sterilization: 30 minutes at 121 C. Volume: 100 ml. in 500 ml. fiask Temperature: 25 C. Incubation: 72 hours on a reciprocating shaker (170 cycles 'per minute) B. Second stage-- Inoculum source: from first stage Medium: same as first stage Sterilization: 40 minutes at 121 C. Volume: 480 ml. in 2000 ml. flask Temperature: 25 C. Incubation: 48 hours on a reciprocatingshaker (120 cycles per minute) The results of the fermentation are given inthe following table (with respect to two batches) Batch 1 2 Assay vs. S. C'ere- Assay vs. S. Cere- Fermentatlon visae dliution units vitae-dilution units;

Age, hours pH pH Extracted! Broth 1 Extracted Broth Samples were centrifuged (the assays on the supernatant being reported as Broth), and the centrilugate extracted with a volume of butanol equal to the original sample (the assays on this extract being reported as Extracted).

6 Example 2.-Shake flask fermentation of Streptomyces nodosus An appropriate inoculum, prepared in the manner described in Example 1, is introduced into a fermentation medium containing:

Soybean meal 10 gm. Ground whole potato 10 gm. Dextrose 10 gm. CoCl .-6H O 10 ml. of 0.05% solution CaCO 1 gm. Distilled water 1 liter.

The medium is sterilizedby autoclaving at 121 C. for 20 minutes prior to the introduction of the inoculum. At the end of four days, assays were run against Saccharomyces cerevisiae with a portion of the broth which has been lyophilized and reconstituted with water to about 2 /3 times the original concentration, (on both the clear supernatant broth and on the butyl alcohol extract of the washed cells, restored to the original sample volume) giving the following results:

S. cerevisia assay,

dilution units/ml. Broth supernatant-fluid 5000' Cell extracts 5000 As a result of these assays, the fermentation is carried out 'for five days, at the end of which time a test of the broth for activity shows it to be active against Candida albicans in a disc test.

Amphotericin maybe extracted from the whole broth in the manner illustrated by the following examples:

Example 3.-Is0pr0pan0l extraction from. whole broth Extraction of amphotericin produced in Example 1 from the whole "broth is carried out by adding to of the broth volume of isopropanol and adjusting to a pH of 2.0 with sulfuric acid. After agitation for about /2 hour, the mixture is filtered, preferably with the use of a filter-aid. The pH of the filtrate .is readjusted to about 7 with sodium hydroxide, and the isopropanol distilled oif under vacuum at a temperature not greater than 35 C. The mixture is then placed in a cold room overnight, the precipitate which forms it filtered off, washed with acetone, and dried in vacuum. A mixture of amphotericin A and amphotericin B is obtaincd in a yield of about 40%. The mixture assays about 1500-2500 d.u./mg. (Saccharomyces cerevisiae).

Example 4.--Batan0l extraction from whole broth To 9.4 liters of whole broth, assaying 3,000 d.u./ml., is added one-fourth of its volume of butanol. The pH is lowered to 2.0 with sulfuric acid, and the mixture is agitated well from one-half hour. Hyflo (5% w./v.), or other filter aid, is then added, and the mixture filtered. The filtrate is placed in a separatory funnel and the butanol layer separated and retained. The butanol solution is then distilled down to /3 its original volume under vacuum at a temperature no greater than 35 C. A precipitate forms, which is filtered off, washed well with acetone, and vacuum dried. The product, which is obtained in about 22% yield, is a mixture of amphotericin A and amphotericin B, and assays about 1600 d.u./mg. against Saccharomyces cerevisiae and about 960 d.u./mg. against Candida albicans.

Example 5.-Extracti0n of amphotericin from mycelium by centrifuging, and the mycelial cake is extracted three more times with 100 ml. portions of n-propanol. The combined propanol extracts are concentrated in vacuo to a small volume of about 130 ml., at which point a precipitate forms. This precipitate is centrifuged down and dried in a vacuum. About 1.114 gm. are recovered, with a potency of about 1176 Candida albicarns d.u./mg. 820 mg. of this solid is finely ground and dissolved by warming in a mixture of 80 ml. of n-butanol and 16 ml. of methanol While 80 ml. of water is gradually added. To this solution 48 ml. of hexane is added, and the mixture stirred and allowed to stand at room temperature over night. A crop of pale yellow crystals of amphotericin is formed, which is filtered and dried in a desiccator. Further crops of less pure material may be obtained by concentrating the mother liquors in vacuo.

Example 6.-Extractin firom basic whole broth To a 500 sample of amphotericin-containing whole broth assaying 11,000 d.u./ml. Saccharomyces cerevisiae is added an equal volume of isopropyl alcohol. The pH of this mixture is then raised to 10.5 using 20% sodium hydroxide. This mixture is then stirred for onehalf hour, 2% Hyflo (W./v.) is then added, and. it is filtered. The pH of the filtrate is lowered to 7, using 20% sulfuric acid, and the isopropyl alcohol removed under vacuum at a temperature no greater than 35 C. After standing overnight, the precipitate is filtered off, washed with water, then with acetone, and dried in vacuum. The yield amounts to about 1.22 g. (77%) of a mixture of amphotericin A and amphotericin B, which assays about 3400 d.u./mg. (Saccharomycscerevisiae).

The amphotericin mixtures may be fractionated into their components, amphotericin A and amphotericin B, by the processes illustrated in the following examples:

Example 7.-Crystallization using alcohol basis.

Example 8.Crystallizati0n using dimethyl formamide The amphotericin obtained in Example 6 is slurried in dimethyl formamide (1 g./20 ml). With stirring, the pH is lowered to 7, using concentrated hydrochloric acid. After stirring for one-half hour, Hyfio (1% w./v.) is added, and the mixture filtered. To the filtrate is added one volume of methanol followed by the slow addition of one volume of water. (Although a methanol-water solution is preferred, ethanol, acetone, or dioxanein water are also effective.) The mixture is then allowed to stand overnight at the resulting pH of 4.5. The precipitate thus formed is filtered ofli, Washed with acetone and dried. It is composed of 85-90% amphotericin B, 10% amphotericin A, and a minor amount of other impurities.

The pH of the resulting mother liquor from which amphotericin B has been isolated is then raised to- 8 by addition of sodium hydroxide, and an additional 3 volumes of water is added. After standing overnight, the precipitate is filtered 01f, washed with acetone and dried. This precipitate is composed of 80-85% amphotericin A, 510% amphotericin B, and a minor amount of other impurities.

The overall activity recovery amounts to 90-95%.

'8 The fraction containing predominantly amphotericin B can be further purified by slurrying it in 70% aqueous isopropanol, at a concentration of 1 g. per 100 ml. at pH 2 for'one-half hour. The mixture is then filtered, the filtrate warmed to 45 C., and the pH slowly raised to 5 with sodium hydroxide. This mixture is then allowed to cool slowly to room temperature and stand overnight. The crystalline product (about 50% yield) is then filtered 01f, washed with'acetone and dried. It represents substantially pure amphotericin B.

The fraction containing predominantly amphotericin A can be further purified by slurrying it in dimethylformamide at a concentration of 1 g. per 20 ml., stirring for one hour, filtering oif the insolubles and adding the filtrate slowly to an equal volume of 50% aqueous methanol. The crystalline precipitate is filtered oif after standing overnight, washed with acetone and dried. Substantially pure amphotericin A is obtained thereby in approximately 70-80% yield.

Fractionation and crystallization of the products obtained in Examples 1 through 5 also may be carried out by the methods of either Example 7 or 8, the latter being preferred, however, due to the higher yields of pure fraction obtained.

Salts and complexes of amphotericin may be prepared according to the methods of the following examples:

Example 9.Preparati0n of alkali metal salts of amphotericin Amphotericin, either the crude mixture or in the form of purified crystals of either amphotericin A or B, readily form salts, and the following process is equally effective in forming either the sodium or potassium salt of the mixture or the purified A or B components: Crystalline amphotericin A is suspended in an amount of methanol such that the concentration of the antibiotic is about 250,000 u./ml. (Saccharomyces grevisiae). Two equivalents of 1 N methanolic sodium hydroxide are added, and the mixture is stirred for 15 minutes to assure complete solution of the antibiotic. The solution is filtered and 10 volumes of acetone are added to the filtrate. A precipitate of the sodium salt is formed thereby, which is filtered off, washed with acetone, and dried in a desiccator. The yield of the sodium salt is about of the original amphotericin based on its biological activity (in vitro).

The sodium salt has a much greater solubility in water (50-60 mg./ml.) than the original crystalline amphotericin A. It also has good solubilityin methanol and diemthyl formamide. It is somewhat soluble in ethanol and isopropanol, but insoluble in ether, acetone, butanol, chloroform, benzene, hexane, and dioxane.

Example 10.Preparati0n of the calcium chloride complex Example 11.-Preparati0n of an acid salt i V Crystalline amphotericin A or B (or a mixture thereof) is dissolved in dimethyl formamide (1 g./25 ml.), and an equivalent of concentrated hydrochloric acid is added thereto. The mixture is filtered and ten volumes of acetone are added to the neutral filtrate; The precipitate formed thereby is filtered off, washed with acetone, and

dried in a vacuum desiccator. 'The product, which is obtained in about 'aj9 0% yield, contains one equivalent of acid and has an 'invitro bioactivity equivalent to that of the crystalline amphoteiicin. .It is somewhat more soluble in water and much more soluble in methanol, ethanol, isopropanol and butanol than is the crystalline amphotericin. The acid salt, however, is insoluble' in acetone, chloroform, ether, benzene, ethyl acetate and hexane. 1 4

The sulfate has been prepared in the same manner by substituting an equivalent of sulfuric acid for the hydrochloric acid. It has properties similar to the hydrochloride.

CHEMICAL AND PHYSICAL PROPERTIES OF AMPHOTERICI-N Crystalline amphoteficin A has the following physical and chemical characteristics:

Melting point: Darkens at 180-185 C, browns and shrinks at 198-200 C. melts with decomposition at about 210 C. p

Elementary analysis: I

:30.48 '(by diiference) No other elements present No methoxy or acetyl'groups Specific optical rotation: M1 163 (pyridine); +93 (acetic acid); 136 (dimethyl formamide); +28 (0.1 N HCl in methanol).

Solubility: 'Good solubility in glacial acetic acid and dimethyl formamide. Soluble to the extent of about 1 mg/ml. in methanol, aqueous isopropyl alcohol and wet butanol, much more soluble in these solvents when acidified or "highly alkalinized. (For example, in a 50 isopropyl alcohol solution, the solubility'o'f amphotericin A is, as 'stated, approximately 1 mg./ml. at pHs between 3 and 8; at pHs of 2, i9, and 10, however, the solubility is 3 mg./.ml. whereas at pH 11, the solubility .has increased to 8-10 mg.'/ ml.).

The antibiotic is insoluble in water at neutral or acid pHs under ordinary conditions, but is soluble at pH 10 and above. In dilute solutions, however, "the antibiotic may be dissolve'din a neutral aqueous solution by raising the pH of a suspension of the material to 11 as, for example, with sodium hydroxide. The solution thus formed may then be neutralized with an acid without any precipitation occurring.

Amphotericin A is insoluble in ether, dioxane, ethyl v I )tmax. (m if Some of the adsorption in the 362-405 region may be due to the presence 'of some amphotericin B.

Infrared spectrum: The infrared absorption "spectrum of amphotericin A suspended in Nu'jol mull is repro -duced in Figure 1.

Amphotericin A shows peaks {and shoulders indicated as sh) at the following frequencies and Wave lengths:

Frequency (cmr Wavelength Frequancyi(crn.- Wavelength 3.00 -8. 86 5.90 9.05 6.04 9. 38 15.16 5h" 9.66 exsssn 9.92 6.47 l. 10.08 7:02'sh '10. 24 sh 7:13 1 '10. 54 7.28sh, 10.96 7.56 11. 20 7. 84 sh ll. s. 12 11.76 8. 32'sh 11.96 "8.45 12.34 '8. 63 12.60 13.16

Neutral equivalent of crystalline amphotericin Az 929 titrated as a'ba'se 989 titrated as an acid pH stability: Stable as all pHs between 3 and 1 1 for at least as long as 24 hours. At a pH as low as 2, amphotericin A is stable for as long as 3 hours with only a small amount of decomposition taking place.

Thermal stability: Stable up to about 70 C. in a neutral solutionof isopropanol.

Chemical tests: Yields a yellow "color with ferric chloride.

Crystalline 'amphotericin B has the following physical and chemical characteristics:

Melting point: No distinct melting point; darkens and chars.

Elementary analysis:

C=56.70% H=7.72% N=1.87% O=33.7l% No other element present No methoxy or acetyl groups Specific optical rotation: [u] +238 (dimethyl -torma'mide); 52.2 (0.1 N HCl in methanol).

Solubility: Good solubility in dimethyl formamide and glacial acetic acid. Soluble to the extent of 0.5 mg./ml. in methanol, aqueous isopropyl alcohol and wet butanol, and much more soluble in these solvents when acidified or highly alkalinized.

Ultraviolet spectrum: The ultraviolet absorption maxima of crystalline amphotericin B in methanol are:

X Max. (m i'f Frequency (cmr!) Wavelength Frequency (cmr Wavelength '(u) (1) Neutral equivalent of crystalline amphotericin B: 760 titrated as a base.

The pH stability and thermal stability of amphotericin B is similar to the corresponding stabilities of amphotericin A.

BIOLOGICAL PROPERTIES OF THE AMPHOTERICINS The amphotericin, as the mixture and as purified amphotericin A and amphotericin B, possess a wide antifungal spectrum, as shown by the following tabulation:

Mixed Am- Ampho- Amphophotericins, tericin A, tericin B,

M10 in MIC in M10 in 'ylml. 'y/DJL 'y/mi.

Saccharomycea cerevisiee 8.1 3.1 25 Aspergillus fumigatus- 3. 1 3. 1 100 Aspergillus Myer". 3. 1 3. 1 100 Penicillium 'rwtatum 3. 1 3. 1 100 C'eratostomella ulmi- 1. 6 1.6 3. 1 Candida albicans 1. 6 1. 6 6. 3 'Irichophyton mentagrophytes 9583 1.6 1.6 12. 5 Microspormn audouim' 12. 5 3.1 100 Microsporum cents. 3.1 3.1 100 Botrytis tulipae- 6. 3 6. 3 100 Rhodotorula glutim's." 3.1 3.1 100 Fusarium bulbigenium 6. 3 6. 3 100 The above tabulation does not represent a true indication of the activity of amphotericin B, since this antibiotic is extremely insoluble, and hence its effectiveness determine the effectiveness of amphotericin as the mixture and as pure amphotericin A and pure amphotericin B, against Candida albicans. The conditions and results of representative tests with eggs (Table II) and mice (Table IH) are as follows:

15 In both tests, the antibiotics used were: (1) a mixture of amphotericin A and amphotericin B dissolved in dimethyl acetamide and then diluted with water so that the final ratio of antibiotics to solvent was 1 to 10 (hereinafter referred to as Base); (2) a mixture of sodium salts of amphotericin A and amphotericin B dissolved in dimethyl acetamide and then diluted with water so that the final ratio of antibiotic to solvent was 1 to 10 (hereinafter referred to as Na salt), and (3) a mixture of the hydrochloride salts of amphotericin A and amphotericin B dissolved in dimethyl acetamide and then diluted with water so that the final ration of antibiotic to solvent was 1 to 10 (hereinafter referred to as HCi salt).

TABLE II [Seven-deyold eggs were infected with 100 L'Dau. standardized inoculum via the yolk sac. One hour after infection, the eggs were treated via the yolk sac with the designated antibiotic at the level indicated below.]

Level Average Difierence Survived/ Antibiotic Tested Survival in Survival Total PDao (mg/egg) Time Time (after 10 (mg/egg) (hours) (hours) days) ControlDi.methyl Acetnmiflo 9G O/lZ r 3-; a it? an 011 166 0/12 0 29 v 0.05 149 +53 0/12 3-; a at 3/11 Na 2 011 173 +71 1 12 0 36 0.05 116 +20 0/12 3-: a a a 3 1 1 :1 1 9 1,11 4

TABLE III [Male mice weighing 21-25 grams were infected intravenously with 0.6 m1. saline suspension containing 4X10" cells (2x10 cells/mouse). Immediately after injection the mice were treated per os (p.o.) or subcutaneously (s.c.) twice daily for two days with the indicated antibiotic at the level indicated below.]

Daily Average Difference Survived] PDao Antibiotic Treatment Route Survival in survival Total (mg/mouse Time Time (after 10 X2 days) (hours) (hours) days) mgJmouse mgnlkg.

Control, 0.5 ml. 8811116---- 31 0/10 7 0.063 240 209 10/10 Base 0.032 167 136 6/10 0. 028 1. 2

Na salt 0. 032 223 192 9/10 0. 019 0. 8

V 0. 016 171 140 4/10 p p 0.063 218 188 9/10 H01 salt... 0. 032 199 168 8/10 0. 024 1. 0

Control 0.5 m1. saline n 30 0/10 3'36 iii; 56% 3/13 p.o- Base 0. 032 p.o 82 52 1/10 044 9 0. 016 13.0- 44 +14 0110 0. p.o--.- 240 210 10/10 0.063 p.o 182 152 5/10 0 063 2 7 0. 032 n.0,.-- +51 0/10 0. 016 11.0---- 46 +16 0110 0. 125 11.0.--- 240 210 10/10 0.063 11.0---- 240 210 10/10 0 041 1 7 0. 032 p.o- 114 84 1/10 0. 016 p.o.-.- 70 40 1/10 1 Figure represents total daily doses, i.e.: 0.063=0.0315 mg./mouse, b.i.d. 3 Reed & Muenchs method;

mgJkg. calculated on a 23 g. average mouse.

- chlorotetracycline or tetracycl-ine,,iniplace of nystatin .to

overcome the resultant fungal-ascendancy;

nystatin-is made by comparing-their effectiveness against Candida albicans in mice. A mixture ofamphotericin A and amphotericin B is dissolved in pure dime'tliyl acetarnide to a'final ratio of 1 part of, amphotericin 'to 10 parts of dimethylacetarnide. The solution is then diluted with distilled water. Forthetest, male mice Weighing l9 2-3 grains. are infected with Candida .albicans by the "intravenous route, each mouse receiving 2x10 'cells as determined by readingsfin, a .colorimeter.v These mice are then treated, either I subcutaneously -(s.c.) or per os (p.o.)' twice daily-for two days with the drug indicated in Table, V below. The mice are observed for 10 days TABLE'IV LD ineggs 111360.111 mice. (ad Lm in mice (adto... in mice (admin'is- 7 (administered ministered intraministered orally tered subcutaneously), Antibiotic by yolk sac),'; fperitoneally in a in 0.025% agar, (mg/kg.) 7

(mg/eg dimethyl .aeetasuspension), (mg./ mide 801.), -(mg./ kg.)

Base (Crystal1ine) 10,000 i,800 (16% suspension 10 000 I m I Base' L o hilized '8.0 28. V 7 Na saitfu i L: 84) 200.'0 10,000 12fi4i;(i)gn8% aqueous so- H01 salt s. 33 6, 00o

COMPARISON "OF AMPHOTERICIN OTHER ANTIBIOTICS Since amphotericin, both as the-mixture and individually, displays certain characteristics similar to those ulated in Table V.

( 240 hours), and any animals surviving 240 hours are assigned a value of 240 hours for the ,purposes'of 'calculation of averagesu'rvival'time. The results are tab- TnnLE Daily Average Difference Survived] Antibiotic Treatment Route Survival in Survival Total mg. Time Time (after 10 mouse/day) (hours) (hours) days) Control, 0.5 m1. saline so. .g 51 /3 s.c. Nystatin s.c. ane 8.0. 010 Amphotemin l 0. 5.0. 240 191 10 Control, 0.51111. saline pm. 3 p.o 3-8 225 as its p.o. AmPhOtericm 0.5 p.o. 240 191 10 10 of other antibiotics, comparative physical and biological tests have been conducted to establish that they are new antibiotics, not previously produced or disclosed.

Amphotericin possesses a high order of activity as compared to nystatin and Rimocidin. A comparison of a purified mixture of amphotericins A and B with a purified batch of nystatin against two test organisms, is as follows:

These results show the superior properties of amphotericin in comparison with nystatin and Rimocidin, against Saccharomyces cerevisiae and Candida albicans.

Further comparison between the amphotericin and Aside from the above biological differences, amphoten'cin differs physically from nystatin, Rimocidin and Ascosin as shown by the following specific optical rotation and ultraviolet spectrum adsorption comparisons:

SPECIFIC ROTATION DATA ON AMPHO'IERIOIN A, AM-

:[liIgFERICIN B, NYSIATIN, RIMOCIDIN, AND ASCOSIN Solvent 0.1 N H01 Antibiotic in Pyridine Acetic Dimethyl methanol acid tormamide Degrees Degrees Degrees Degrees Amphotericin A +136 +28 Amphotericin B. +238 -52. 2 Nystatin +11 7 +6. 5 3. 5 Rimocidin, S04 +102 +67 Ascosin (50% w./w.

NaHOOa) +12. 2 ---13 The data in this table is considered in conjunction with the known ultraviolet absorption data for the two amphotericins, it is evident that amphotericin A, although it has an ultraviolet spectrum which is similar to that reported for nystatin and Rimocidin, is differentiated therefrom by the respective specific rotations; and similarly, although amphotericin B has an ultraviolet spectrum which is very similar to that of Ascosin, the two are distinguished by the difierences in their respective specific rotations.

The conclusion from these comparisons, therefore, is

that the amphotericin differs from nystatin, Rimocidin, or Ascosin both in biological effects and physical characteristics.

The invention may be variously otherwise embodied within the scope of the appended claims.

We claim:

1. A process for producing amphotericin, which comprises cultivating a strain of Streptomyces nodosus in an aqueous nutrient medium comprising an assimilable, fermentable carbohydrate and an assimilable organic nitrogen source, under submerged aerobic conditions, until substantial anti-fungal activity is imparted to said medium and recovering amphotericin from the medium.

2. A substance effective in inhibiting the growth of fungi, selected from the group consisting of, amphotericin B and the salts thereof, said amphotericin B being an amphoteric substance having the following elementary analysis: C=56.70%, H=7.72%, N=1.87%, O=33.71%; that possesses a crystalline structure in the pure state; has a specific optical rotation, as measured by the D line of sodium at 24 C. of +238 in dimethyl formamide and 52.2 in 0.1 N HCl in methanol; is soluble in glacial acetic acid; has an ultraviolet absorption spectrum measured in methanolic HCl with bands at the following wave lengths: 345, 362, 382 and 405 millimicrons and respective extinction coefficients of 390, 830, 1380 and 1540; an infrared absorption spectrum when suspended in hydrocarbon oil in solid form as shown in Figure 2;and a neutral equivalent when titrated as a base of about 760.

3. Amphotericin B, as described in claim 2.

4. An alkali metal salt of amphotericin B, as described in claim 2.

.claim 2.

. 16 5. A sodium salt of .a mphotericin B as described. in claim 2.

6. A hydrochloride salt of amphotericin B as described inclaimZ.

.7. A sulphate of amphotericin B as described in References Cited in the file of this patent Abst. of Paper No. 14, 15, 113,114 and 11s presented at Antibio. Symposium, 1956 (5 pp.).

Blank: A.M.A. of Dermatologyyvol. 75, Febru- Hosoya: The H. of Antibiotics, Ser. A., April 1955, pp. 48-50.

Drug Trade News, November 7, 1955, pp. 51 and 84.

Oroshnik, Science, February 4, 1955, pp. 147-155.

Schatz eta1.: Mycologia, vol. 40, No. 4, 1948, pp. 461, 462, 473, 475-477.

Waksman: The Actinomycetes, pub. 1950, by Chronica Botanica Co., Waltham, Mass., pp. 116-117.

Dutcher et al.: Art. in Antibiotics 'Annual, 1953-54, pp. 191-194, by Med. EncycL, Inc., N.Y.C.

Waksman: The Actinomycetes and Their Antibiotics, pp. 174, 176, 177, 182, 183 and 184. Pub. 1953 by Williams and Wilkins Co., Balt., Md.

Smith et al.: Antibiotics and Chemother. pp. 962-970, September 1954.

Alexopoulos: Ohio I. of Science, vol. 41, 1941, pp. 425-430.

Alexopoulos et al.: Bull. of the Torrey Botanical Club, April 1942, vol. 69, No. 4, pp. 257-261.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,908,611 October 13, 1959 James Do Dutcher et al0 It is herebfi certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line '73, after "base" insert me such as sodium hydroxide or potassium hydroxide. The column 4, line 4, strike out "such as sodium hydroxide or potassium hydroxide The"; column 6, line '72', for "cycelium" read mycelium column "7, line '7, for "albicarns", in italics, read albicarls M in. italics;

Signed and sealed this 12th day of April 1966.

ROBERT C. WATSON Commissioner of Patents KARL H. AXLINE Attesting Ofiicer 

2. A SUBSTANCE EFFECTIVE IN INHIBITING THE GROWTH OF FUNGI, SELECTED FROM THE GROUP CONSISTING OF, AMPHOTERICIN B AND THE SALTS THEREOF SAID AMPHOTERICAN B BEING AN AMPHOTERIC SUBSTANCE HAVING THE FOLLOWING ELEMENTARY ANALYSIS: C=56.70%, H=7.72%, N=1.87%, 0=33.71%; THAT POSSSESSES A CRYSTALLINE STRUCTURE IN THE PURE STATE; HAS A SPECIFIC OPTICLA ROTATION AS MEASURED BY THE D LINE OF SODIUM AT 24* C. OF +238* IN DIMETHYL FORMAMIDE AND -52.2* IN 0.1N HCL WITH BANDS AT THE BLE IN GLACIAL ACETIC; HAS AN ULTRAVIOLET ABSORPTION SPECTRUM MEASURED IN METHANOLIC HCI WITH BANDS AT THE FOLLOWING WAVE LENGTHS: 345, 362, 382 AND 405 MILLIMICRONS AND RESPECTIVE EXTINCTION COEFFICIENTS OF 390, 830, 1380 AND 1540; AN INFARARED ABSORPTION SPECTRUM WHEN SUSPENDED IN HYDROCARBON OIL IN SOLID FORM AS SHOWN IN FIGURE 2; AND A NEUTRAL EQUIVALENT WHEN TITRATED AS A BASE OF ABOUT
 760. 